Air-pump.



J. DICKENS.

AIR PUMP.

'APPLICATION FILED NOV. 4, 1903.

Patented J au. 24, 1911.

lZzvez 'for' d 70 721 E nu: mmm: PETERS cm, wAsHINcroN. D. c.

UNTED STAT JOI-IN DICKENS, 0F PASSAIC, NEW JERSEY.

AIR-PUMP.

To all 'whom 'it may concern:

Be it known that l', JOHN Dronnxs, a citizen of the United States, residing at Passaic, in the county of Passaic and State of New Jersey, have invented new and useful Improvements in Air-Pumps, ot which the following is a speciication.

My present invention relates to improvements in air pumps and especially to that class adapted for the inflation of pneumatic tires or for other purposes, and it has for its object to provide an improved pump of this character which is comparatively simple and inexpensive in its construction and which in operation is capable of compressing at each stroke of the piston or plunger a quantity of air or other fluid of a volume greater than that which is ordinarily compressed at each stroke of pumps of the usual construction7 a compound compression of the air being accomplished although the pump may contain a single cylinder and piston, a pump being thereby provided which has a relativ-ely large capacity although it is relatively small or compact and its construction is simple, containing as it does a few parts which are not liable to get out of order or require frequent repairs.

To these and otheriends, the invention consists in certain improvements, and combinations and arrangements ot' parts, all as will be hereinafter more fully described, the novel features being pointed out particularly in the claims at` the end ot the speciiication.

In the accompanying drawing. Figure l represents a longitudinal section of an air pump constructed in accordance with my invention; Fig. 2 represents a transverse section of the pump on the line 22 of Fig, l, and Figs. 3 and 4 are perspective views ot the elements of the upper air valve.

Similar parts are designated by the same reference characters in the several views.

Pumps constructed in accordance with my present invention are capable of use for various purposes,.and in the accompanying` drawing, l have shown one specific embodiment of the invention which is especially adapted for the inflation of pneumatic tires or for. similar purposes in which cases, a relatively small pump of large capacity is desirable. It will be understood, however, that the invention is not limited to the specific embodiment shown, as cer- Specication of Letters Patent.

Application filed November 4, 1908.

Patented Jan. 24.-., 1913i.

Serial No. 461,061.

tain modiiications in the construction and arrangement of the parts may be made in order that the invention may be applied to the best advantage in each particular case.

In the present instance, the pump comprises a cylinder l of a suitable length and diameter, the lower end of this cylinder being threaded or otherwise iitted tightly into a base 2, the latter being formed ot a casting or otherwise and it preferably has a pair of lateral extensions which form a pair of toot rests 3 upon which the feet of the'operator may rest during the operation of the pump. A piston or plunger '-l is mounted to reciprocate axially of the cylinder and it is operable by a piston rod 5, the upper end ot which may be provided with a suitable handle S by means of which the piston may be reciprocatod. cap 7 is threaded or otherwise tightly litted upon the upper end of the cylinder and has a stutingbox 8 through which the piston rod operates, the stulling-box preventing the escape of air around the piston rod during the upward or return strokes of the piston. A double-acting piston is employed in the present instance, and while a piston of any suitable construction may be employed which is capable of compressing air upon both sides, I prefer to employ a piston having a pair of cup-shaped packing washers 9 and l0, these packing cups being firmly clamped by the nuts ll and l2 against the upper and lower sides of the piston and they are arranged in reverse relation so that upon the lip-stroke ot the. piston, the upper packing cup will compress air in the upper portion ot the cylinder while a down-stroke ot the piston will cause the packing cup 10 to compress air in the lower portion o't the cylinder.

An air inlet 13 is formed in the base and it communicates with the space at the bottom of the cylinder. A check valve is provided which permits air to enter the lower end of the cylinder through the air inlet and it prevents discharge of air through the inlet. A check valve of any suitable construction may be employeth that shown in the present instance comprising a ball 14- which is acted upon by a spring` which normally tends to seat it and thereby close the air inlet. An apertured bushing 16 may be threaded or otherwise fitted into the base and this bushing coperates with the spring llt) and by adjusting the bushing the tension of the spring may be adjusted. By removing the bushing, the spring and the ball-valve are rendered accessible. A discharge 17 is also formed in the base and may be connected by the nipple 1S to the device which is to be supplied with the compressed air. In using the pump for theintlation of pneumatic tires, the usual iiexible tube may be attached to this nipple, and the check valve of the tire in such instances, serves as a check valve for the discharge passage of the pump. Air is also admitted to the upper portion of the cylinder through an inlet 19 which is preferably formed in the cap 7, and this inlet is also controlled by a suitable check-valve whereby air may be admitted to the upper portion of the cylinder through this inlet, but it is prevented from escaping therethrough. 1n the present instance, a check-valve is employed which consists of a disk Q0 of leather, rubber or other material which is preferably flexible and this disk has a central aperture 21 through which the piston rod passes loosely. This disk coperates with a flat surface Q2 which is formed at the under side of the cap 7 and serves as a valve seat, and when the disk is in a position to open the inlet 19 and permit entrance of air to the upper portion of the cylinder, the disk then rests upon a supporting disli 23, the latter being of a diameter preferably greater than that of the `valve disk 2O and it rests upon the top of the tube which forms the air cylinder. A suitable number of recesses Q4: are formed preferably in the periphery of the supporting 'disk 23 so as to permit air to pass around the valve disk and through these recesses into the upper portion of the cylinder. The piston rod also passes loosely through a central aperture 25 formed in the disk 23.

During the operation of the pump, as will hereinafter appear, air passes from the upper to the lower side of the piston, and in the `present instance, the piston rod 5 is provided with a by-passage Q6 which extends upwardly from the lower end of the piston rod and in a direction axially thereof, and this axial passage communicates with the space above the piston through a vent 27. it. valve chamber is formed in the lower end of the piston rod and contains a suitable cheek-valve which will permit air under appropriate pressure to pass from the upper to the lower side of the piston during the upstroke of the latter. The check-valve shown in the present instance consists of a ball 28 which seats against the valve seat 29 surrounding the aXial passage Q6. and a spring 30 serves to retain the ball in cooperative relation with its seat. This spring is loaded heavier than the spring .15 of the inlet valve, and this may be accomplished either by making the spring 3() of heavier material or by adjusting` it under a greater tension by means of a bushing` 31 which is threaded into the lower end of the piston rod and bears against the spring, this bushing being apertured to permit the passage of air therethrough.

lin operating a pump constructed in accordance with the present embodiment of my invention, it will be assumed that the nipple 1S of the pump is connected by a tube or .other suitable means to a tire or other device having a check or non-return valve. As

the piston rises from its lowermost position in the cylinder, a supply of air will enter the lower end of the cylinder through the inlet, the check valve thereof opening due to the vacuum pressure beneath the piston. This same upward movement of the piston causes the air in the upper portion of the cylinder to be compressed, the valve disk Q0 rising so as to close the inlet 19. When the body of air in the upper portion of the cylinder is compressed sufficiently to overcome the pressure of the spring 30 which retains the valve 2S upon its seat, this valve will open, allowing the compressed air in the upper portion of the cylinder to pass the piston and enter the lower portion of the cylinder, the valve 14 .of the inlet closing, and the remaining portion of the upward or return stroke of the piston serves to transfer the air from the Lipper to the lower portion of the cylinder. Upon thc down-stroke of the piston, the valve 28 will close under the pressure of lair in the lower portion of the cylinder and, as the piston descends, the body of air in the cylinder will be forced out through the discharge passage 17. During the descending movement of the piston, the valve disk 20 will leave the valve-seat 22 so as to rest upon the supporting disk 23, the inlet 19 being thereby opened so that air enters the upper portion of the cylinder therethrough.

A pump constructed in accordance with my present invention is capable at each power stroke of the piston of compressing a volume of fluid greater than that which would be drawn into the cylinder during each stroke of an ordinary single-acting pump, as a part of the air or other fluid behind or above the piston is compressed and is introduced into the cylinder at the compression side of the piston during each return stroke thereof and such air is given a. second compression during its discharge from the pump. The result is that thel capacity of the pump is increased without enlarging its dimensions, thus providing 'a pump which is admirably adapted for use in the inflation of pneumatic tires or in other connections where the pump is essentially portable, such for instance as where the pump is used as a part of the equipment of an automobile. Moreover,

the pump is not only compact in its dimensions, but it is comparatively simple in its construction, as a compound compression of the air is practically effected, although a single cylinder and piston only is used, and the arrangement of the various working parts of the pump is such that they are not liable to injury.

l claim as my invention l. A pump comprising a cylinder, valves for admitting air alternately to the opposite ends thereof, a piston reciprocable in said cylinder and capable of introducing and compressing air at both sides thereof whereby a body of air introduced into one end of the cylinder is compressed during one stroke of the piston, and means for introducing a body of air into the opposite end of the cylinder while the body of air in advance of the piston is being compressed and for transferring the body of compressed air in advance of the piston to the rear side of the piston when Ythe compression of such body' of air reaches a predetermined point during the stroke of the piston, the neXt stroke of the piston causing a recompression of both bodies of air.

2. A pump comprising a cylinder, a reciprocatory piston capable of introducing and compressing air at both sides thereof, valves for admitting air alternately to the opposite ends of said cylinder, and means for introducing a body of air compressed at one side of the piston to the opposite side thereof and for causing a second compression of such air.

3. A pump comprising a cylinder, a reciprocatory piston havingy a passage through it and a valve for permitting air to be transferred from one to the other side of the piston through said valve, means for introducing and compressing air at both sides of said piston, and means for causing air to be introduced into the space at one side of said piston partially from the atmosphere and partially through said passage from the space in advance of the piston while the piston moves in one direction.

et. A pump comprising a cylinder, a reciprocatory piston capable of receiving and compressing air at both sides thereof and having a passage therethrough controlled by a loaded valve, and means for causing a volume of air to be introduced from the Vatmosphere in rear of said piston during air compressed at one side of the piston to the space in rear thereof after a quantity of air has been drawn into said space from the atmosphere.

6. A pump comprising a cylinder, a reciprocatory piston, check valves for admitting' air alternately to the opposite ends of the cylinder, and a check valve for transferring air compressed at one side of said cylinder to the space at the opposite side thereof after said piston has traversed a portion of its stroke in one direction and has drawn into the space behind said piston a quantity of air from the atmosphere.

7. A pump comprising a cylinder, a reciprocatory piston, a discharge being provided at one end of said cylinder, an air inlet valve arranged at the same side of the cylinder with said discharge, a check valve for admitting air to the opposite end of the cylinder, a by-passage between the two sides of the piston being formed in the piston, and a check valve held closed with a force suflicient to insure the opening of said by-passage to admit compressed air from the forward side of the piston to the space at the discharge end of the cylinder after the piston has traversed a portion of its return stroke.

S. A pump comprising a cylinder, a reciprocatory piston, check-controlled inlets for admitting and causing compression of air at opposite sides of said piston during its operation, a by-passage being formed in the piston and communicating with the opposite sides thereof, and a check-valve capable of opening to permit air to be transferred from one to the other side of said piston after the latter has traversed a por tien of its stroke in one direction.

9. A pump comprising a cylinder, a reciprocatory piston having air inlet valves at oppositeaends and a discharge passage at one end, a lay-passage being formed in the piston and communicating with the spaces at opposite sides thereof, and a checkvavle controlling said ley-passage and arranged to open toward that end of the cylinder provided with the discharge passage, said check-valve being provided with a spring of a strength sufficient to retain it in closed position until after the piston has traversed a portion of its stroke whereby a volume of compressed air will be transferred from one to the opposite side of said pistou preparatory to a secondary compression and discharge thereof.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

JOHN DICKENS.

lVitnesses NELLIE FARLEY, IRA J. BOGERT. 

